EP3519262B1 - Device for cleaning an optical sensor of an optical detection system for a motor vehicle - Google Patents

Description

The present invention relates to the field of driving assistance devices and optical detection systems used for this purpose, and it relates more particularly to cleaning devices intended to project at least one fluid towards a surface to be cleaned of a. motor vehicle, such as an optical sensor of an optical detection system for a vehicle.

The document FR 3 021 014 discloses the preamble of claim 1.

Optical detection system is any system comprising optical sensors such as cameras, laser sensors or other sensors based on the emission and / or detection of light in the spectrum visible or invisible to humans, in particular the light. 'infrared.

Such optical detection systems are equipping a growing number of motor vehicles in order to help the driver of the vehicle in certain driving situations, one of which, well known, is the parking aid. For this assistance to be as effective as possible, the data supplied by the optical detection system must be of the best possible quality, and it is therefore essential to have own sensors to carry out these data acquisitions. To do this, a cleaning device can be ordered to inject, on a sensor of the optical detection system (for example the lens of a picture taking camera), a cleaning fluid just before the detection is carried out (for example the shooting).

These cleaning devices must not interfere with the operation of the optical sensor, that is to say that they must in particular not be located in the field of vision of the sensor, and they must also be as compact as possible to meet the requirements. the space constraints of the vehicle. For this, most often, the cleaning devices comprise a movable part between a cleaning position, deployed, in which the dispensing orifices that the movable part comprises are located in the vicinity of the surface of the sensor to be cleaned, and a position of rest, in which this movable part is retracted so as not to interfere with optical detection by means of the sensor in question.

The movable part forms a piston housed in a jack cylinder. It is known to use the pressure of the cleaning fluid admitted into the cylinder to cause the displacement of the piston towards its cleaning position, the cleaning fluid being moreover intended to enter an internal duct of the mobile part, at least when this is in the cleaning position, to then be injected via the dispensing orifices.

The cleaning fluid enters an inlet chamber formed in the body via an inlet port made in a tip of the cylinder, and the fluid present in the chamber pushes on one end of the piston movable in the body. The piston then slides along an integral tongue rod.

It is known to provide, at the free end of the fixed rod, integral with the cylinder and along which the piston slides, grooves into which the cleaning fluid is capable of being inserted from a first upstream end facing the chamber d. 'admission. Up to a determined relative position of the piston with respect to the rod, the sliding takes place in a sealed manner: the position of the piston completely covers the grooves formed in the thickness of the rod. The fluid present in the chamber is stopped by a sealing element and cannot access the passage grooves, so that the flow of the fluid to the distribution orifices is blocked.

Beyond a defined position, the grooves are no longer covered by the piston at their first upstream end, and this allows the passage of the fluid in the grooves, between the rod and the piston, towards the interior of the piston. moving part up to the distribution orifices.

For example, the document FR3021014 discloses such a cleaning device in which the fixed rod integral with the cylinder peripherally comprises a plurality of grooves each forming a passage for the cleaning liquid. As explained above, the ejection of the fluid can only take place when the movable part reaches a determined position relative to the rod and therefore when the distribution orifices arranged at the end of this movable part reach a determined position facing the optical sensor. . At this stage, the cleaning fluid massively enters the internal duct, the ends of the grooves being released simultaneously.

A drawback of this embodiment is that the cleaning fluid comes out with a maximum flow rate from the start to the end of the spraying and the absence of variation in the flow rate prevents any optimization of the consumption of the fluid.

The object of the present invention is to provide a cleaning device, intended to project at least one fluid towards a surface to be cleaned of a motor vehicle, such as an optical sensor of an optical detection system which, by an arrangement and a particular sizing of the cleaning fluid passage channels, makes it possible to sequence the ejection of cleaning fluid through the intake ports, so that the consumption of fluid is optimized and that the cleaning efficiency of the optical sensor is improved .

• un corps creux fermé à une extrémité par une bride d'entrée,
• un piston mobile en coulissement le long d'un axe longitudinal dans le corps creux et porteur à une première extrémité d'un élément de distribution de fluide de nettoyage, le piston étant mobile entre une position extrême rétractée et une position extrême déployée,
• une tige solidaire de la bride d'entrée qui s'étend parallèlement à l'axe longitudinal et le long de laquelle coulisse le piston mobile,
• des moyens d'acheminement de fluide de nettoyage à travers le corps creux, depuis un embout d'admission de fluide jusqu'à l'élément de distribution, comprenant au moins une chambre d'admission dont le volume varie en fonction du déplacement du piston mobile et un conduit de distribution ménagé dans le piston mobile,
• le piston et/ou la tige sont configurés pour prévoir entre eux des canaux de passage de fluide de nettoyage.

The first object of the invention is a cleaning device intended to project at least one fluid towards a surface to be cleaned of a motor vehicle, such as an optical sensor of an optical detection system for a vehicle, comprising:

• a hollow body closed at one end by an inlet flange,
• a piston movable in sliding along a longitudinal axis in the hollow body and carrying at a first end a cleaning fluid distribution element, the piston being movable between an extreme retracted position and an extreme deployed position,
• a rod integral with the inlet flange which extends parallel to the longitudinal axis and along which the movable piston slides,
• means for conveying cleaning fluid through the hollow body, from a fluid inlet nozzle to the distribution element, comprising at least one inlet chamber, the volume of which varies according to the displacement of the piston mobile and a distribution duct formed in the mobile piston,
• the piston and / or the rod are configured to provide between them channels for the passage of cleaning fluid.

The cleaning device according to the invention is characterized in that at least two passage channels have axial dimensions, along the axis. longitudinal, different, each passage channel having an axial dimension distinct from that of the neighboring channels in the circular series arrangement of the channels.

According to the invention, the "conveyance means" of the cleaning fluid group together all the conduits, inlet chambers and / or passage channels which make it possible to bring the cleaning fluid from the inlet or zone of admission to the distribution element. These conveying means contain at least one distribution duct formed in the movable piston, which preferably consists of two portions of different diameters. The enlarged upper part of the distribution duct is defined so as to allow the sliding of the rod in the movable piston while the lower part of said duct makes it possible, by its smaller diameter, to pressurize the fluid so as to eject it. on the optical sensor for cleaning.

According to the invention, “the displacement means” of the piston are formed at least in part by the means for conveying the fluid, in particular by the pressure of said cleaning fluid exerted on said piston.

• les canaux de passage soient agencés parallèlement à l'axe longitudinal ;
• au moins deux canaux de passage présentent des dimensions radiales variables ;
• au moins un canal de passage est interrompu le long de la dimension longitudinale ; les canaux de passage peuvent s'interrompre puis redémarrer, de telle sorte que le passage de fluide longitudinal entre la tige et le piston est interrompu, à l'endroit de ces portions sans canal.

According to different characteristics of the invention, taken alone or in combination, it is possible to provide that:

• the passage channels are arranged parallel to the longitudinal axis;
• at least two passage channels have variable radial dimensions;
• at least one passage channel is interrupted along the longitudinal dimension; the passage channels can be interrupted and then restarted, so that the passage of longitudinal fluid between the rod and the piston is interrupted, at the location of these channelless portions.

By the expression “axial dimension” is meant the height of a passage channel, in the direction of the longitudinal axis of elongation of the movable piston, while by “radial dimension” is meant the depth of said channel, in the thickness of the part of the movable piston and / or of the rod in which the passage channels can be formed.

The passage channels can be formed by grooves formed in the movable piston and / or in the rod, and covered by the rod, respectively by the piston. The particular arrangements and dimensions of the grooves forming the passage channels make it possible to vary the flow rate of fluid by having more or less large passage sections. It is therefore understood that the cleaning fluid will flow primarily through the passage channel having the largest axial dimension. Whatever the geometries and radial dimensions of the passage channels, it is necessary to maintain a sufficient range between two consecutive channels in order to allow optimum guidance of the piston around the rod.

• le canal de passage qui présente la plus grande dimension axiale présente la plus petite dimension radiale ; on comprend dès lors que l'augmentation de la dimension radiale d'un canal de passage permet d'augmenter le débit de passage du fluide ; il est particulièrement avantageux de pouvoir augmenter le débit de fluide projeté par l'élément de projection sur le capteur optique lorsque l'élément de projection est correctement déployé ;
• le dispositif de nettoyage comporte au moins trois canaux de passage ;
• les canaux de passage sont agencés en série autour de l'axe longitudinal, avec une évolution progressive des dimensions axiales des canaux de passage du début à la fin de la série.

According to another series of characteristics, it can be provided that:

• the passage channel which has the largest axial dimension has the smallest radial dimension; it is therefore understood that increasing the radial dimension of a passage channel makes it possible to increase the flow rate of the fluid; it is particularly advantageous to be able to increase the flow rate of fluid projected by the projection element onto the optical sensor when the projection element is correctly deployed;
• the cleaning device has at least three passage channels;
• the passage channels are arranged in series around the longitudinal axis, with a progressive evolution of the axial dimensions of the passage channels from the start to the end of the series.

In a preferred embodiment of the cleaning device, the latter comprises a fluid inlet nozzle formed projecting from the inlet flange and eccentric with respect to the longitudinal axis on which the hollow body is centered. The fluid inlet nozzle opens inside the hollow body into an inlet chamber delimited at least in part by the inlet flange, a peripheral wall of the hollow body and by the movable piston.

The passage channels can in particular be formed by a groove made in the movable piston and covered, fully in the extreme retracted position and partially in the other relative positions of the piston and of the stem, by the stem. More precisely, the grooves can be formed on the internal wall of the piston delimiting the distribution duct, these grooves opening onto the intake chamber.

Advantageously, the means for moving the piston comprise, in addition to the means for conveying the fluid capable of putting said cleaning fluid under pressure, elastic means for returning into position, housed in the hollow body to tend to return said rest position to said rest position. piston. Preferably, the elastic means for returning to position are housed in the hollow body to bear against the hollow piston, opposite the intake chamber. In one embodiment, the elastic means for returning to position consist of at least one compression spring capable of deforming under the effect of the pressure of the cleaning fluid so as to promote the longitudinal movement of the hollow piston. It is thus understood that in the phase of loading the fluid into the device, the hollow piston moves opposite the intake chamber then performs a reverse return path at the end of the cleaning phase by ejection of the fluid. .

• le piston creux comporte une partie centrale sensiblement cylindrique, apte à coulisser au sein d'un manchon de guidage creux ménagé à l'extrémité du corps creux opposé à la bride d'entrée, une partie terminale de distribution prolongeant la partie centrale et à l'extrémité libre de laquelle l'élément de distribution est apte à être fixé, et une partie d'admission prolongeant la partie centrale à l'opposé de la partie terminale de distribution et configurée pour coulisser à l'intérieur dudit corps creux ;
• les canaux de passage comportent respectivement une rainure ménagée dans le piston le long de la partie d'admission ;
• la partie terminale de distribution du piston est agencée pour que le conduit de distribution ménagé dans le piston puisse communiquer avec un canal de distribution de l'élément de distribution ;
• le piston comporte, au voisinage de son extrémité amont, une couronne, contre une face de laquelle peut prend appui le moyen élastique de rappel ; de préférence, ladite couronne comporte une gorge périphérique agencée dans sa paroi extérieure et apte à accueillir un élément d'étanchéité, de telle manière que le piston équipé dudit élément, puisse coulisser de manière étanche au sein du corps creux ;
• une gorge périphérique peut être agencée à une extrémité libre de la tige, pour accueillir un joint d'étanchéité, de telle manière que la tige, équipée dudit joint, puisse coulisser de manière étanche dans la partie centrale du piston.

According to a series of characteristics, it can be expected that:

• the hollow piston comprises a substantially cylindrical central part, capable of sliding within a hollow guide sleeve formed at the end of the hollow body opposite the inlet flange, a distribution end part extending the central part and at the end 'free end of which the dispensing element is able to be fixed, and an inlet part extending the central part opposite the end dispensing part and configured to slide inside said hollow body;
• the passage channels respectively comprise a groove formed in the piston along the intake part;
• the end distribution part of the piston is arranged so that the distribution duct formed in the piston can communicate with a distribution channel of the distribution element;
• the piston comprises, in the vicinity of its upstream end, a crown, against a face of which the elastic return means can bear; preferably, said crown has a peripheral groove arranged in its outer wall and adapted to receive a sealing element, such that the piston equipped with said element can slide in a sealed manner within the hollow body;
• a peripheral groove can be arranged at a free end of the rod, to receive a seal, so that the rod, fitted with said seal, can slide in a sealed manner in the central part of the piston.

According to another characteristic of the invention and with the aim of being part of an overall hydraulic diagram, the device for cleaning a sensor can comprise, in addition to the inlet nozzle, the hollow body, the rod and the piston. mobile carrying passage channels, a cleaning fluid storage tank, and elements for controlling the circulation of cleaning fluid between the tank and the inlet nozzle. Said control elements may consist of a pump and optionally of a solenoid valve and are configured to block the admission of cleaning fluid into the inlet nozzle in a rest position, to supply the nozzle. intake of cleaning fluid in order to move the dispensing element into a cleaning position on the one hand and to spray cleaning fluid on the other hand, and to block the cleaning fluid in the intake chamber and the channel of dispensing and hold the dispensing element in the cleaning position.

When integrated into the hydraulic system, the solenoid valve is a 3-way solenoid valve capable of allowing or stopping the passage of a pressurized fluid in three different positions in order to allow circulation from the pump to the cylinder or to prevent any circulation or even allow the return of liquid from the cylinder to the reservoir.

A second object of the invention relates to a motor vehicle equipped with an optical detection assembly characterized in that it comprises at least one cleaning device as described above, intended to project at least one fluid towards a surface to be cleaned. a motor vehicle, such as an optical sensor of an optical detection system for a vehicle.

• la figure 1 est une vue en perspective éclatée d'un dispositif de nettoyage selon l'invention, destiné à projeter au moins un fluide vers une surface à nettoyer d'un véhicule automobile, tel qu'un capteur optique d'un système de détection optique, le dispositif de nettoyage comportant au moins un piston mobile en coulissement dans un corps creux le long d'une tige fixe et portant à une extrémité un élément de distribution du fluide ;
• la figure 2 est une vue en coupe du piston du dispositif de l'invention, suivant un plan perpendiculaire à l'axe longitudinal (X) de la figure 1, au niveau d'une partie d'extrémité à l'opposé de l'extrémité portant l'élément de distribution de fluide, illustrant un exemple de mode de réalisation et de répartition de canaux de passage ménagés circonférentiellement sur une paroi intérieure dudit piston ;
• la figure 3 est une vue en coupe, dans un plan de coupe comprenant l'axe longitudinal (X), du dispositif de nettoyage de la figure 1 lorsque le piston mobile est en position extrême rétractée, ou position de repos, et la figure 3a est une vue de détail de l'extrémité libre de la tige autour duquel coulisse le piston dans cette position de repos rétractée ;
• la figure 4 est une vue en coupe, dans le même plan de coupe que celui de la figure 3, du dispositif de nettoyage de la figure 1, dans une première position intermédiaire dans laquelle le fluide de nettoyage est autorisé à passer à l'intérieur du piston mobile par le biais d'une quantité limitée de canaux de passage, et la figure 4a est une vue de détail de l'extrémité libre de la tige autour duquel coulisse le piston dans cette première position intermédiaire ;
• la figure 5 est une vue en coupe, dans le même plan de coupe que celui de la figure 3, du dispositif de nettoyage de la figure 1, dans une deuxième position intermédiaire dans laquelle le fluide de nettoyage est autorisé à passer à l'intérieur du piston mobile par le biais d'une quantité importante de canaux de passage, et la figure 5a est une vue de détail de l'extrémité libre de la tige autour duquel coulisse le piston dans cette deuxième position intermédiaire ;
• la figure 6 est une vue en coupe, dans le même plan de coupe que celui de la figure 3, du dispositif de nettoyage de la figure 1, lorsque le piston mobile est en position extrême déployée ;
• la figure 7 est une représentation schématique de l'architecture hydraulique associée au dispositif de nettoyage selon l'invention ;
• la figure 8 présente un premier exemple d'évolution du débit d'un fluide de nettoyage au cours d'un déplacement du piston mobile entre une position extrême rétractée, de repos, et une position extrême déployée ;
• la figure 9 présente un deuxième exemple d'évolution du débit d'un fluide de nettoyage au cours d'un déplacement du piston mobile entre une position extrême rétractée, de repos, et une position extrême déployée, dans un cas particulier où l'un des canaux de passage est interrompu ; et
• la figure 10 est une vue d'ensemble d'un élément support d'un système de détection optique et d'un dispositif de nettoyage associé, tel qu'il peut être monté sur un élément de carrosserie d'un véhicule automobile.

Other features, details and advantages of the invention and its operation will emerge more clearly on reading the description given below by way of indication, in relation to the appended figures, in which:

• the figure 1 is an exploded perspective view of a cleaning device according to the invention, intended to project at least one fluid towards a surface to be cleaned of a motor vehicle, such as an optical sensor of an optical detection system, the cleaning device comprising at least one movable piston sliding in a hollow body along a fixed rod and carrying at one end a fluid distribution element;
• the figure 2 is a sectional view of the piston of the device of the invention, along a plane perpendicular to the longitudinal axis (X) of the figure 1 , at an end portion opposite the end carrying the fluid distribution element, illustrating an exemplary embodiment and distribution of passage channels formed circumferentially on an inner wall of said piston;
• the figure 3 is a sectional view, in a section plane including the longitudinal axis (X), of the cleaning device of the figure 1 when the movable piston is in the extreme retracted position, or rest position, and the figure 3a is a detail view of the free end of the rod around which the piston slides in this retracted rest position;
• the figure 4 is a sectional view, in the same section plane as that of the figure 3 , the cleaning device of the figure 1 , in a first intermediate position in which the cleaning fluid is allowed to pass inside the movable piston through a limited number of passage channels, and the figure 4a is a detail view of the free end of the rod around which the piston slides in this first intermediate position;
• the figure 5 is a sectional view, in the same section plane as that of the figure 3 , the cleaning device of the figure 1 , in a second intermediate position in which the cleaning fluid is allowed to pass inside the movable piston through a large number of passage channels, and the figure 5a is a detail view of the free end of the rod around which the piston slides in this second intermediate position;
• the figure 6 is a sectional view, in the same section plane as that of the figure 3 , the cleaning device of the figure 1 , when the movable piston is in the extreme deployed position;
• the figure 7 is a schematic representation of the hydraulic architecture associated with the cleaning device according to the invention;
• the figure 8 presents a first example of the evolution of the flow rate of a cleaning fluid during a movement of the movable piston between an extreme retracted position, of rest, and an extreme deployed position;
• the figure 9 presents a second example of the evolution of the flow rate of a cleaning fluid during a movement of the movable piston between an extreme retracted position, of rest, and an extreme deployed position, in a particular case where one of the channels of passage is interrupted; and
• the figure 10 is an overall view of a support element of an optical detection system and of an associated cleaning device, such as it can be mounted on a bodywork element of a motor vehicle.

First of all, it should be noted that if the figures set out the invention in detail for its implementation, they can, of course, serve to better define the invention where appropriate. It will also be understood that the embodiment of the invention illustrated by the figures is given by way of non-limiting example. Consequently, other configurations of the device according to the invention can be produced, in particular by variations in the arrangement, the distribution and the axial and / or radial dimensioning of the passage channels, which will necessarily impact the flow rates of the cleaning fluid. and associated pressures.

It is also recalled that, in the description which follows, the names “upstream” and “downstream” refer to the direction of flow of the cleaning fluid in the cleaning device according to the invention. Thus, the denomination "upstream" refers to the side of the device according to the invention by which this cleaning fluid is admitted into it, and the denomination "downstream" refers to the side of the device according to the invention by which the fluid of cleaning is distributed outside thereof, to a surface of an optical sensor of an optical detection assembly of a motor vehicle.

The figure 1 illustrates a cleaning device 100 intended according to the invention to project at least one fluid towards a surface to be cleaned of a motor vehicle, such as an optical sensor 30, and it has been illustrated elsewhere on figure 10 A sight a support element 101 configured to receive an optical sensor 30 and a juxtaposed cleaning device 100.

The cleaning device consists essentially, from upstream to downstream along a longitudinal axis (X) of elongation of the cleaning device, of a fluid inlet nozzle 11, of a flange d 'inlet 2, a rod 10 integral with the inlet flange 2, a piston 3, an elastic return means in position 4 and a distribution element 8, 9. Each of these components is housed inside, or fixed at one end, of a hollow body 1 of revolution about a longitudinal axis (X).

The fluid inlet nozzle 11 is formed projecting from the inlet flange 2, and it extends opposite the hollow body, being here eccentric with respect to the longitudinal axis (X) of the body hollow 1. The inlet nozzle 11 has a longitudinal bore passing through and opening out inside the hollow body 1 in an inlet chamber 14 (visible in particular on the figures 4 to 6 ) delimited at least in part by the inlet flange 2, a peripheral wall of the hollow body 1 and by the movable piston 3.

The inlet flange 2 is configured to close the upstream end of the hollow body 1. A sealing member 5 may be provided at this closure. The inlet flange is configured to support the rod 10 on its internal face, facing the interior of the hollow body.

The rod 10 protrudes from the inlet flange 2, inside the hollow body 1. The rod has a cylindrical shape with a circular section, the outer peripheral face of which is smooth. The free end 15 of the rod 10, which extends opposite the inlet flange 2, comprises a peripheral groove 23 adapted to receive a sealing O-ring 6 so as to allow the sealed sliding of the rod 10 in the piston 3. As will be described below, the O-ring seal 6 is configured to bear against an internal face of the piston so that the fluid is blocked upstream of the O-ring seal between the rod and the piston, since the grooves formed in the piston do not allow the escape of fluid towards the distribution element.

The piston 3 carries at a first end, or downstream end, a cleaning fluid distribution element 8, 9 consisting in the illustrated example of two complementary L-shaped parts.

The piston 3 comprises, in the vicinity of its upstream end, that is to say the end facing the inlet flange 2, a ring 21 on the outer wall of which is arranged a peripheral groove 22, capable of accommodating a sealing element 7 so as to allow the sealed sliding of the piston 3 in the hollow body 1. The sealing element 7 is preferably a lip seal, capable of limiting the friction of the piston 3 in the hollow body 1 .

The piston is hollowed out from one end to the other by an internal duct for circulating the cleaning fluid. The hereinafter specific internal shape of the piston will be described in more detail, in particular in that it has a plurality of grooves configured to form passage channels of variable lengths which allow passage of liquid at a controlled rate.

The movable piston 3 slides in the hollow body 1 between an extreme retracted position, or rest position (visible on the figure 3 ), and an extreme deployed position, or cleaning position (visible on the figure 6 ).

The cleaning fluid is injected into the hollow body via the inlet nozzle to then be ejected through the distribution orifices. Means for conveying the cleaning fluid through the hollow body 1, from the fluid inlet nozzle 11 to the distribution element 8, 9, comprise at least the inlet chamber 14 and a duct distribution 13 (visible on figures 3 to 6 ) housed in the movable piston 3.

The elastic return means 4, preferably a helical spring, is arranged in the hollow body between the peripheral wall and the piston, so as to bear at one end on the bottom of the body and at the opposite end on a face of crown 21.

The piston is mounted in the hollow body around the rod 10 which extends substantially coaxially with the movable piston 3, so that at least the free end 15 of the rod 10 extends inside the duct internal distribution 13 of the movable piston 3. The hollow piston 3 comprises portions substantially cylindrical which can be defined, from upstream to downstream, as being an inlet part 19 carrying the crown 21, a central part 16 able to slide within a hollow guide sleeve 18 formed at the downstream end of the hollow body 1 and an end distribution portion 17, of smaller diameter, at the free end of which the distribution element 8, 9 is able to be fixed. The distribution duct 13 formed in the movable piston consists of at least two portions of different diameters, including a first proximal part 131 extending from an upstream end of the duct, that is to say an end opening on the intake chamber 14, and a second distal portion 132 extending from the downstream end of the conduit. As shown on figures 3 to 6 , a constriction zone 130 is arranged between the proximal and distal parts of different diameters.

The enlarged first proximal part 131 of the distribution duct 13 is defined so as to allow the relative sliding of the rod 10 with respect to the movable piston 3 while the second lower part of said duct 13 allows, by its smaller diameter and the narrowing zone which results therefrom, to pressurize the fluid so as to eject the latter onto the optical sensor 30 with a view to cleaning it. The terminal distribution part 17 of the piston 3 is arranged so as to cooperate with the upstream portion 8 of the distribution element so that the second lower part of the distribution duct 13 can communicate with a distribution channel 20 formed in the element. distribution 8, 9.

The piston 3 and / or the rod 10 are configured to provide between them passage channels 12 which allow the flow of cleaning fluid from the inlet chamber 14 (visible on the figure). figure 3 ), the variable volume of which is defined as a function of the position of the piston 3 relative to the inlet flange 2. The passage channels 12 are obtained by grooves 120 made in the outer wall of the rod, respectively in the inner wall 31 of the piston, these grooves being closed by the piston, respectively the rod. In the embodiment illustrated by figure 1 , the passage channels are each formed by a groove 120 formed in the inner wall of the piston 3 delimiting the internal distribution duct 13 along the inlet part 19 and closed by the covering of the smooth outer peripheral face of the rod 10.

The intake part 19 thus has grooves 120 while the central part 16 of the piston is smooth. The relative sliding of the piston with respect to the rod is thus a sealed sliding, preventing the passage of fluid, when the sealing O-ring 6 formed in the free end part 15 of the rod 10 is located in the central part 16 of the piston and therefore bears continuously on the periphery of the piston, while it consists of a permeable sliding, allowing the passage of fluid, when the O-ring seal 6 is located in the inlet part 19.

According to an essential characteristic of the invention, the grooves 120 participating in forming the passage channels 12 have different dimensions from each other, and in particular different longitudinal dimensions, so as to be able to control the gradual arrival of cleaning fluid in the distribution element 8.9.

The figure 2 illustrates an embodiment of the invention and presents an example of the arrangement, distribution and sizing of the grooves 120 forming the passage channels 12 formed on the inner wall 31 of the piston 3. A sufficient range 121 is maintained between two grooves consecutive. By sufficient range is meant that whatever the configuration of the grooves and their number, the rod and the piston have a sufficiently large contact surface with respect to the holes left by the grooves, in order to allow stable guidance of the piston around the rod. In this example, eight channels are formed by the association of one of the eight grooves formed in the inner wall 31 of the piston 3 and of the rod bearing against this inner wall. In a variant not shown, provision can be made for the passage channels to be formed by grooves formed on the outer peripheral face of the rod and by the inner wall of the piston covering these grooves, it being understood that it is important according to the invention that the grooves participating in forming the passage channels are of different lengths for at least two of them.

According to the invention, these grooves 120 forming the passage channels 12 are configured such that one of these grooves has an axial dimension, that is to say a dimension along the longitudinal axis (X), distinct from the axial dimension of at least one other of the grooves. A possible configuration of the different heights, or axial dimensions, of the grooves participating in forming the fluid passage channels of a cleaning device according to the invention will be described below.

These grooves 120 extend axially, between a proximal end 122, opening onto an end face 210 of the ring 21 which participates in delimiting the intake chamber 14, and a distal end 123, in the thickness of the mobile piston3. and extending to a determined axial dimension of this proximal end face 210 of the crown 21.

These grooves 120 participating in forming the passage channels 12 can also have radial dimensions or variable depths. Provision can in particular be made for the groove which has the largest axial dimension to have the smallest radial dimension, it being understood that the increase in the radial dimension of a passage channel makes it possible to increase the flow rate of the fluid provided by this passage. passage channel. It is particularly advantageous to be able to increase the flow rate of fluid projected by the projection element onto the optical sensor when the projection element is correctly deployed.

An example of controlled deployment of the dispensing element in the cleaning device according to the invention will now be described in more detail, with particular reference to the figures 3 to 6 , which illustrate successive stages of deployment.

The figure 3 illustrates the cleaning device of the invention in a first rest position, according to which the dispensing element 8, 9 is in the retracted position and housed in the lower part of the body of the cleaning device 100. The piston is then arranged to so that the inlet part 19 is pressed against the inlet flange, the inlet chamber 14 then being reduced to a minimum volume. In this rest position, the elastic return means is in the uncompressed state defining the free length of the spring 4.

It is notable that in this rest position, the free end 15 of the rod 10 extends deeply into the internal distribution duct 13 formed in the movable piston, such that this free end 15 of the rod is located substantially in the vicinity of the constriction zone 130. In this rest position, the grooves 120 arranged in the piston 3 are entirely covered by the rod 10 so that at the distal end 123 of each of these grooves, the passage channels are closed. The presence of the sealing O-ring 6, arranged in the peripheral groove 23 of the rod and dimensioned to rub against the internal wall of the piston, makes it possible to ensure the seal and to prevent the passage of fluid towards the element. distribution.

In this rest position, fluid is injected into the cleaning device when a cleaning action of an optical sensor is commanded. The fluid is distributed between the inlet flange and the movable piston, in the inlet chamber 14, and furthermore fits into the passage channels, each groove forming a passage channel having a free proximal end 123 which opens out. on the end face 210 of the crown 21, and which is therefore accessible from the intake chamber. As has just been described, the grooves are covered by the piston in this intermediate position and the fluid entering the channels remains blocked there.

The figure 4 illustrates the cleaning device according to the invention in a first intermediate position between the rest position and the extreme deployed position. This first intermediate position is obtained following the sliding of the piston along the rod, under the effect of the pressure of the cleaning fluid, in particular against the crown 21 of the piston 3, of the cleaning fluid continuing to be injected by the nozzle. admission. In this first intermediate position, the piston has slid along the rod so that the free end 15 of the rod 10 has moved away from the constriction zone 130: the seal 6 is no longer at the level of the central part 16 of the piston but at the level of the inlet part 19 in which the grooves 120 extend. The rod and the O-ring seal 6 no longer cover the distal end 123 of the groove 120 having the largest axial dimension, the O-ring seal being disposed between this disengaged distal end and the end face 210 of the ring 21. The cleaning fluid present in this groove can then infiltrate into the distribution duct 13, as shown by arrow F1 visible on the figure 4 , and fluid can flow from the inlet chamber 14 to the distribution element 8, 9 through the single passage channel, the distal end of which is not covered. This results in a passage of fluid at a reduced flow rate of fluid, substantially equal to 1 / n, n being the number of passage channels arranged between the rod and the piston, here eight in number.

The figure 5 illustrates a second intermediate position between the extreme rest position and the extreme deployed position, in which the cleaning fluid is allowed to pass inside the movable piston through the channels, a significant proportion of which, here five out of eight, is discovered at its distal end. In this second intermediate position, the piston slid further along the rod so that the free end 15 of the rod 10 has moved closer to the upstream end of the duct, that is to say the end opening onto the inlet chamber 14. The seal 6 is located at the level of the inlet part 19 in which the grooves 120 extend, with the rod and the O-ring seal 6 which do not overlap. plus the distal end of five of the grooves 120, i.e. the distal end of the five grooves having the largest axial dimension. The fluid can circulate from the inlet chamber 14 to the distribution element 8, 9 through the five corresponding passage channels and this results in a passage of fluid at an intermediate flow rate, substantially equal to 5 / n, n being the number of passage channels arranged between the rod and the piston, here eight in number.

The figure 6 illustrates the extreme deployed position, that is to say the position of maximum deployment of the cleaning device and total ejection of the fluid thanks to the increase in the flow rate to 100% per passage of fluid in each of the passage channels 12 The back pressure exerted by the spring 4 and / or the stop of the crown 21 of the piston against the hollow guide sleeve 18 makes it possible to limit the movement of the rod relative to the piston and to prevent the rod from escaping out of it. of the distribution duct 13 formed in the piston 3. In this stop position, the distal end of each of the channels is released and the seal 6 only has the effect of blocking the passage of fluid between the two walls internal and external of the piston and the rod, without obstructing the passage in the grooves. The distribution element 8, 9 is then fully deployed outside the cleaning device so as to adopt an optimal position of cleaning of the optical sensor 30, and the fluid ejection rate is then maximum.

Thanks to the different axial dimension of the grooves, it is thus possible to control the ejection flow rate as a function of the deployment of the distribution element and of the position of the fluid jet on the optical sensor which results therefrom.

At the end of this cleaning phase by ejection of all of the fluid, the piston, after having moved away from the intake chamber, performs a reverse return path under the combined effect of the return of the spring and stopping the supply of fluid via the inlet nozzle, the spring then pushing the piston back to its original position by pushing the remaining fluid out of the inlet chamber and out of the hollow body. It should be noted that the axial offset of the distal ends of the grooves makes it possible to avoid the presence of too sudden overpressure when the piston returns to position in the hollow body.

The figure 7 schematically illustrates the overall hydraulic architecture associated with the cleaning device 100 which may include, in addition to the inlet nozzle 11, the hollow body 1, the rod 10 and the movable piston 3 carrying passage channels with different axial dimensions, a reservoir storage 24 for the cleaning fluid and elements for controlling the circulation of cleaning fluid between the reservoir 24 and the inlet nozzle 11 of said cleaning device 100, which is, here, schematically represented by a jack. Said control elements may consist of a pump 25 and optionally of a solenoid valve 26.

It is understood that at the end of the cleaning phase by ejection of all of the fluid, the fluid, under the effect of the return of the piston pushed by the spring into the rest position, passes through the inlet nozzle and then returns to the pump and to the storage tank.

The figure 8 illustrates the variation in the flow rate of cleaning fluid projected onto an optical sensor as the movable piston moves between a retracted rest position and an extreme deployed position. It can be noted that, unlike what would have been the case with a device of the prior art, with which the start variation would have taken the form of an on / off slot, with a flow rate at 0% before obtaining a single intermediate position in which the piston no longer covers the end of the grooves and a flow rate at 100% after passing from this single intermediate position, here we have a progressive evolution in stages, allowed by the variation of the axial dimension from one passage channel to another.

• un premier canal de passage 12a présente une dimension axiale plus grande que celle des autres ;
• un deuxième canal de passage 12b, non forcément agencé au voisinage direct du premier canal dans l'agencement en série circulaire des canaux, présente une dimension axiale moindre que celle du premier canal de passage mais supérieure à celle des autres canaux ;
• un troisième canal de passage 12c, non forcément au voisinage direct du deuxième canal dans l'agencement en série circulaire des canaux, présente une dimension axiale moindre que celle du deuxième canal de passage mais supérieure à celle des canaux autres que le premier et le deuxième ;
• un quatrième canal 12d et un cinquième canal 12e, non forcément directement voisins dans l'agencement en série circulaire des canaux, présentent des dimensions axiales égales, et moindres que celle trois premiers canaux de passage ; et
• un sixième canal 12f, un septième canal 12g et un huitième canal 12h, non forcément directement voisins dans l'agencement en série circulaire des canaux, présentent des dimensions axiales égales entre elles, et moindres que celle de tous les autres canaux de passage.

In this example, it should be noted that:

• a first passage channel 12a has an axial dimension greater than that of the others;
• a second passage channel 12b, not necessarily arranged in the direct vicinity of the first channel in the circular series arrangement of the channels, has an axial dimension smaller than that of the first passage channel but greater than that of the other channels;
• a third passage channel 12c, not necessarily in the direct vicinity of the second channel in the circular series arrangement of the channels, has an axial dimension smaller than that of the second passage channel but greater than that of the channels other than the first and the second ;
• a fourth channel 12d and a fifth channel 12e, not necessarily directly adjacent in the circular series arrangement of the channels, have equal axial dimensions, and less than that of the first three passage channels; and
• a sixth channel 12f, a seventh channel 12g and an eighth channel 12h, not necessarily directly adjacent in the circular series arrangement of the channels, have axial dimensions which are equal to each other, and less than that of all the other passage channels.

In this example, it is understood that when the movable piston is in the rest position, and until it reaches the first intermediate position, no passage channel is discovered and the liquid is blocked, so that the fluid flow rate towards the distribution element 8, 9 is zero. In the first intermediate position, only the first passage channel, that is to say the channel having the longest axial dimension, sees its end cleared by the relative position of the piston with respect to the rod, and the cleaning fluid present in this first passage channel 12a can circulate towards the distribution element via the internal channel 13 of the piston: in an exemplary embodiment where the eight passage channels each have the same depth, that is to say the same radial dimension, the flow rate of cleaning fluid passing to the distribution element is substantially equal to 1/8 ^th . It will be understood that as the piston advances along the rod, the passage channels are successively discovered from above, that is to say the one having the greatest axial dimension, at least above , the flow rate of cleaning fluid increasing. In the second intermediate position shown on the figure 5 , in which are discovered, by way of example, the first five passage channels in the order of their axial magnitude, it is understood that the flow rate of cleaning fluid is substantially equal to 5/8 ^th . It is thus possible to observe a stepwise change in the flow rate passing cleaning fluid towards the distribution element, with, in the example illustrated in FIG. figure 8 , a first level at 12.5%, a second level at 25%, a third level at 37.5%, a fourth level at 62.5% and a final level at 100%. The progressive evolution on the first stages allows a loading and priming phase of a reduced flow, while the evolution is faster at the end of the movement of the piston, when the cleaning device is in the optimal position for cleaning. the optical sensor.

The figure 9 illustrates another exemplary embodiment in which one of the passage channels has an interruption substantially in its middle. As will be described below, this arrangement makes it possible to adjust the quantity of fluid projected relative to the deployment of the mobile piston and therefore of the cleaning device. It can be noted that the change between the flow rate at 0% and the flow rate at 100% is overall, as it was presented in the first exemplary embodiment figure 8 , progressive in stages, but with a break in the middle of this progression before resuming it.

In this exemplary embodiment, it should be noted that the first three passage channels 12a to 12c are similar to those previously described, as well as the last four passage channels 12e to 12h. On the other hand, the fourth channel 12d differs in that the groove is interrupted so as to form a neutral zone 120d in which the wall of the rod and / or the piston is not machined.

We can thus see, in the example illustrated on figure 9 , a stepwise evolution of the flow from cleaning fluid to the distribution element, initially with a gradual evolution, with a first level at 12.5%, a second level at 25% and a third level at 37 , 5%, then a decreasing evolution with a return to the second level at 25%, so as to limit the projection of fluid in this beginning of movement of the mobile piston, and finally a new progressive evolution, with a jump towards a fourth level 62 % then a final level at 100%. In this last phase of development, the increase is more brutal, the jump from the second level to the fourth level being more marked. This ensures, thanks to this rupture in the passage channel, a pressurized fluid jet allowing, while the movable piston is in a sufficiently deployed intermediate position, more effective cleaning.

The foregoing description clearly explains how the invention makes it possible to achieve the objectives that it has set for itself and in particular to provide a device for cleaning an optical sensor of a motor vehicle which, by an arrangement, distribution and a particular sizing of the cleaning fluid passage channels makes it possible to sequence the filling with fluid by controlling the flow rate of said fluid and the associated pressure and therefore to optimize the fluid consumption and improve the cleaning efficiency of the optical sensor. The present invention is not limited to the embodiments given by way of non-limiting examples.

Claims (13)

1. A cleaning device (100), intended to spray at least one fluid toward a surface that is to be cleaned belonging to a motor vehicle, such as an optical sensor of an optical detection system, the cleaning device comprising at least:

   - a hollow body (1) closed at one end by an inlet flange (2),

   - a mobile piston (3) able to slide along a longitudinal axis (X) in the hollow body (1) and which at a first end bears a cleaning fluid distribution element (8, 9), the piston being able to move between a retracted extreme position and a deployed extreme position,

   - a rod (10) secured to the inlet flange (2) which runs parallel to the longitudinal axis (X) and along which the mobile piston (3) slides,

   - means for conveying cleaning fluid through the hollow body (1), from a fluid intake end-piece (11) as far as the distribution element (8, 9), comprising at least one intake chamber (14), the volume of which varies according to the movement of the mobile piston (3) and a distribution duct (13) formed in the mobile piston (3),

   - the piston (3) and/or the rod (10) being configured to provide between them passageways (12) for cleaning fluid,

   characterized in that at least two passageways (12) have different axial dimensions along the longitudinal axis (X), each passageway (12) having an axial dimension that is distinct from that of the adjacent passageways in the arrangement whereby the passageways are arranged in a circular series.
2. The cleaning device as claimed in claim 1, characterized in that the passageways (12) are arranged parallel to the longitudinal axis (X).
3. The cleaning device as claimed in claim 1 or 2, characterized in that at least two passageways (12) have variable radial dimensions.
4. The cleaning device as claimed in the preceding claim, characterized in that the passageway (12) that has the longest axial dimension has the shortest radial dimension.
5. The cleaning device as claimed in one of the preceding claims, characterized in that at least one passageway (12) is interrupted along the longitudinal dimension (X).
6. The cleaning device as claimed in any one of the preceding claims, characterized in that the passageways (12) are arranged in series around the longitudinal axis (X), with a progressive evolution in the axial dimensions of the passageways (12) from the start to the end of the series.
7. The cleaning device as claimed in any one of the preceding claims, characterized in that the passageways (12) respectively comprise a slot (120) formed in the mobile piston (3) and/or in the rod (10) .
8. The cleaning device as claimed in the preceding claim, characterized in that the slots (120) are formed on the internal wall of the piston (3) delimiting the distribution duct (13), these slots opening onto the intake chamber (14).
9. The cleaning device as claimed in any one of the preceding claims, characterized in that the means for moving the piston (3) comprise, in addition to the fluid conveying means, elastic means (4) housed in the hollow body (1) to tend to return the mobile piston (3) to the extreme rest position.
10. The cleaning device as claimed in any one of the preceding claims, characterized in that the hollow piston (3) comprises a substantially cylindrical central part (16), able to slide inside a hollow guide sleeve (18) formed at the opposite end of the hollow body (1) to the inlet flange (2), a terminal distribution part (17) extending the central part (16) and to the free end of which the distribution element (8, 9) is able to be fixed, and an intake part (19) extending the central part (16) in the opposite direction to the terminal distribution part (17) and configured to slide inside the hollow body (1) .
11. The cleaning device as claimed in the preceding claim, characterized in that the passageways (12) respectively comprise a slot (120) formed in the piston (3) along the intake part (19).
12. The cleaning device as claimed in either one of claims 10 and 11, characterized in that a peripheral groove (23) is arranged at a free end (15) of the rod (10) to accommodate a seal (6) such that the rod (10), fitted with said seal (6), can slide sealingly in the central part (19) of the piston (3).
13. A motor vehicle equipped with an optical detection system and with an associated optical sensor, characterized in that it comprises at least one cleaning device as claimed in any one of the preceding claims, intended to spray at least one fluid toward a surface of the optical sensor that is to be cleaned.

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